Optimized Rumen Fiber-Degrading SynCom 3

"Group 41, consisting of 1 × 108 CFU/mL of S. equinus 5640 and E. lactis 6088, 1 × 106 CFU/mL of P. mucosa 6360, and 1 × 105 CFU/mL of L. delbrueckii 5812 and P. acetatigenes 6076, achieved the highest 48 h NDFD (66.84%), significantly higher than the control group by 20.56%, but had no difference in 48 h DMD and gas production (P < 0.05, Fig.  6 C). The results demonstrated that favorable concentrations and ratios of strains in SynComs are more effective in promoting fermentation performance and facilitating industrial application."

"The fiber degrading strains S. equinus 5640, L. delbrueckii 5812, P. acetatigenes 6076, E. lactis 6088, and P. mucosa 6360 had whole genome sequencing at Biozeron."

"Genome sequence analysis revealed the synergistic and complementary actions of these five bacterial strains in carbohydrate degradation processes."

"Fig. 7 Fiber degradation pathways of the five strains in SynComm 3. A Number of COG genes in carbohydrate transport and metabolism. B–D Venn diagram of genes in glycoside hydrolases (GHs), carbohydrate-binding modules (CBMs), and carbohydrate esterases (CEs) from CAZy database. E Relative abundance of KEGG pathway on level 3. F, G Number of genes involved in fiber degradation, glucose degradation, and VFA synthesis. H Metabolic profiles of fibrous substrates, glucose, and VFA"

"The in situ feeding trial demonstrated that the supplementation of the SynCom significantly altered the rumen fermentation profile and enhanced feed fiber degradation in Huaxi cattle. The ruminal degradation rates of DM, NDF, and ADF exhibited a positive trend in the TRE group, with increases of 2.61%, 7.81%, and 11.47%, respectively, at 72 h compared to the CON group, although these differences were not statistically significant (Fig.  8 A–C, P > 0.05). SynCom supplementation profoundly influenced ruminal VFA production. While the total VFA concentration in the TRE group was significantly lower than in the CON group at 12 h (Fig.  8 F, P = 0.0011), it increased progressively over time, becoming significantly higher in the TRE group at 24 h (P = 0.0196) and 48 h (P = 0.0001), and remaining 10.80% higher at 72 h (P > 0.05). This shift was driven by a significantly elevated acetate concentration in the TRE group at 24, 48, and 72 h (Fig.  8 G, P < 0.05), with no significant difference observed in propionate levels. Consequently, the A:P ratio was significantly elevated in the treatment group at 48 h and 72 h (Fig.  8 M, P < 0.05). The concentrations of butyrate, isobutyrate, and isovalerate in the TRE group were also significantly higher than in the CON group at 24 and 48 h (Fig.  8 I, J, and L, P < 0.05). In contrast, valerate concentration in the TRE group was significantly lower than in the CON group at 48 h (Fig.  8 K, P = 0.0013) and 72 h (Fig.  8 K, P < 0.0001). Concomitantly, the NH3-N concentration was significantly lower in the TRE group at 48 h and 72 h (Fig.  8 E, P< 0.0001 and P = 0.0034, respectively), implying improved nitrogen utilization by the rumen microbiota."